In two of the robberies, police said the suspect stole property from the victims' pockets. In two other robberies, the suspect grabbed a wallet from the victim's hands.
The robberies occurred in the 4700-block of West Madison at 10:48 a.m. on February 2, the 1100-block of South Kedzie at 5:20 p.m. on February 7, the 4000-block of West Chicago Avenue at 10:45 p.m. on February 7 and the 3100-block of West Roosevelt Road at 3:30 p.m. at February 15.
Police said in one of the robberies the suspect fled in a gray van.
The suspect is described as a man, 25 to 35 years old, 5'07 to 6'00, 180 to 200 pounds and black hair.
Anyone with information is asked to contact Area North Detectives (312) 744-8263.